This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A017704 #14 Sep 08 2022 08:44:43
%S A017704 1,1048576,3486784401,1099511627776,95367431640625,1828079220031488,
%T A017704 79792266297612001,1152921504606846976,12157665459056928801,
%U A017704 50000000000000000000,672749994932560009201,638959998741245853696
%N A017704 Denominator of sum of -20th powers of divisors of n.
%C A017704 Sum_{d|n} 1/d^k is equal to sigma_k(n)/n^k. So sequences A017665-A017712 also give the numerators and denominators of sigma_k(n)/n^k for k = 1..24. The power sums sigma_k(n) are in sequences A000203 (k=1), A001157-A001160 (k=2,3,4,5), A013954-A013972 for k = 6,7,...,24. - Ahmed Fares (ahmedfares(AT)my-deja.com), Apr 05 2001
%H A017704 G. C. Greubel, <a href="/A017704/b017704.txt">Table of n, a(n) for n = 1..10000</a>
%t A017704 Denominator[DivisorSigma[-20,Range[20]]] (* _Harvey P. Dale_, Dec 31 2014 *)
%t A017704 Table[Denominator[DivisorSigma[20, n]/n^20], {n, 1, 20}] (* _G. C. Greubel_, Nov 05 2018 *)
%o A017704 (PARI) vector(20, n, denominator(sigma(n, 20)/n^20)) \\ _G. C. Greubel_, Nov 05 2018
%o A017704 (Magma) [Denominator(DivisorSigma(20,n)/n^20): n in [1..20]]; // _G. C. Greubel_, Nov 05 2018
%Y A017704 Cf. A017703.
%K A017704 nonn,frac
%O A017704 1,2
%A A017704 _N. J. A. Sloane_